The present invention relates to three-dimensional image capturing devices comprising an image pickup head which is movable along a path surrounding an object of three-dimensional shape for picking up images of the object three-dimensionally.
The size of shoes is expressed generally in the length of the foot from the heel to the toe. The shape of the foot differs from person to person not only with respect to the length thereof but also in respect of the height and width of the instep, so that in making shoes which fit to a particular person, there is a need to measure the three-dimensional shapes of the feet of the person. It is conventional practice to measure some typical dimensions, such as the length of the foot, the height and width of the instep, with an instrument and prepare a last based on the measurements obtained. However, the conventional method is not only cumbersome and inefficient but also has the problem that the limited number of dimensions still fail to accurately express the three-dimensional shape of the foot.
Accordingly the present applicant developed an apparatus shown in FIG. 6 for measuring the three-dimensional shape of a foot A. The apparatus comprises a rail mechanism 20 in the form of a loop and installed on a base 1 for surrounding an object of measurement, i.e., the foot A, and an image pickup head 3 having a CCD camera incorporated therein and movable along the rail mechanism 20. With this apparatus, a pair of fixed cameras 6, 7 are arranged above the object of measurement, i.e., the foot A, for capturing images of the image pickup head 3 in movement, whereby the position of the head 3 on a fixed coordinate system is measured. The video signal from the CCD camera incorporated in the image pickup head 3 and the video signals from the fixed cameras 6, 7 are fed through signal cables 4, 40 to a control unit 5, which processes the signals as by coordinate conversion to measure the three-dimensional shape of the foot A.
FIG. 4 shows details of the construction of the rail mechanism 20 included in the three-dimensional shape measuring apparatus. The rail mechanism 20 comprises an inner loop wall 21 having the image pickup head 3 in engagement therewith, and an outer loop wall 22 surrounding the inner loop wall 21. A head terminal 42 provided on the head 3 and a signal relay terminal 43 provided on the outer loop wall 22 are interconnected by a signal cable 41. Electric power is supplied from the control unit 5 to the signal relay terminal 43 and further to the head terminal 42 on the image pickup head 3 through the signal cable 41. The video signal obtained from the terminal 42 of the head 3 is fed to the signal relay terminal 43 via the signal cable 41 and further to the control unit 3.
With the rail mechanism 20 shown in FIG. 4, the image pickup head 3 makes a complete circuit along the inner loop wall 21. The signal cable 41 is free to flex with this movement. For example, when the image pickup head 3 returns to the original position after making one circuit counterclockwise, the signal cable 41 assumes the shifted position indicated in a chain line. However, in the course of movement of the head 3 from the position shown in FIG. 4 toward the signal relay terminal 43, the signal cable 41 is bent by being pushed by the head 3 and is therefore likely to move partly slower than the head 3 as shown in FIG. 5. In this case, part of the signal cable 41 is likely to become caught by the head 3 by being brought to therebelow or to move over the outer loop wall 22 to outside.
Accordingly, an object of the present is provide a device for capturing images three-dimensionally which comprises an image pickup head and a signal cable extending from the image pickup head and which is free of the likelihood that the signal cable will become caught by the head or move out of a specified area during the movement of the head.
The present invention provides a device for capturing images three-dimensionally which comprises:
a rail 2 extending in the form of a loop around a three-dimensional object images of which are to be captured,
an image pickup head 3 movable along the rail 2,
a signal cable 8 interconnecting a head terminal 81 provided on the image pickup head 3 and a signal relay terminal 82 provided at a specified position relative to the rail 2,
an auxiliary cable 83 interconnecting a head-side connecting point 85 provided on the image pickup head 3 and a rail-side connecting point 84 provided at specified position relative to the rail 2 and in the vicinity of the signal relay terminal 82, and
a connecting member 9 movable along the rail 2 and having the signal cable 8 and the auxiliary cable 83 slidably reeved therearound for turning back the cables in directions opposite to each other.
The signal cable 8 is provided along a path extending from the head terminal 81 in one direction along the rail 2, turned back on the connecting member 9 and extending along the rail 2 to the signal relay terminal 82, while the auxiliary cable 83 is provided along a path extending from the head-side connecting point 85 in the other direction opposite to said one direction along the rail 2, turned back on the connecting member 9 and extending along the rail 2 to the rail-side connecting point 84. The signal cable 8 is used for supplying electric power from the signal relay terminal 82 to the image pickup head 3 and for feeding an output signal from the head 3 to the signal relay terminal 82. The auxiliary cable 83 is used for operatively connecting the image pickup head 3 to the connecting member 9.
In the case where the image pickup head 3 of the device of the invention moves along the rail 2 in one direction, e.g., in the direction in which the signal cable 8 extends, the auxiliary cable 83 is pulled along by the movement of the image pickup head 3, whereby the connecting member 9 is driven in the same direction as the image pickup head 3. This movement of the connecting member 9 pulls the signal cable 8 extending from the image pickup head 3 toward the direction of movement of the head 3. Accordingly, the signal cable 8 is not slackened by the movement of the image pickup head 3 but remains positioned along the path extending from the head terminal 81 to the signal relay terminal 82 via the connecting member 9.
Alternatively when the image pickup head 3 moves in the opposite direction, i.e. in the direction in which the auxiliary cable 83 extends, the signal cable 8 is pulled along by the movement of the head 3, whereby the connecting member 9 is driven in the same direction as the image pickup head 3. This movement of the connecting member 9 pulls the auxiliary cable 83 extending from the image pickup head 3 toward the direction of movement of the head 3. Accordingly, the auxiliary cable 83 is not slackened by the movement of the image pickup head 3 but remains positioned along the path extending from the head-side connecting point 85 to the rail-side connecting point 84 via the connecting member 9.
Stated specifically, the connecting member 9 has mounted thereon a signal cable post 92 for reeving the signal cable 8 therearound and turning back the cable 8, and an auxiliary cable post 91 for reeving the auxiliary cable 83 therearound and turning back the cable 83. This enables the signal cable 8 and the auxiliary cable 83 to change the course through 180 degrees while slidingly moving around the respective posts without interfering with each other.
Further stated specifically, the rail 2 comprises an inner loop wall 21 and an outer loop wall 22, and the image pickup head 3 is slidably in engagement with the inner loop wall 21 or the outer loop wall 22, the signal cable 8 and the auxiliary cable 83 being accommodated between the inner loop wall 21 and the outer loop wall 22, the signal relay terminal 82 and the rail-side connecting point 84 being provided on the inner loop wall 21. With this specific construction, the portions of the signal cable 8 and the auxiliary cable 83 in contact with the inner loop wall 21 are connected respectively to the signal relay terminal 82 and the rail-side connecting point 84 to remain immovable relative to the inner loop wall 21. This obviates the friction between the inner loop wall 21 and each of the two cables 8, 83, permitting the cables to shift smoothly with the movement of the image pickup head 3.
Thus, the device of the invention for capturing images three-dimensionally is free of the likelihood that the cable will become caught by the head or move out of the specified area.